Yes, they are graded, but the squares appear in the original files. Depending on the size you look at it.
It was shot too dark, so a little over zealous cranking was needed to get them to work. I think it is scaling artifacts. I found some similar issues over on the Blackmagic forums. The footage was shot on an Ursa, and there were other users with sort of similar issues. They said pan and tilt .5 in resolve, but another suggestion noise reduction. I’m trying everything.